By JOHN SULLIVAN

EW YORK -- Oliver Jovanovic was convicted Wednesday of kidnapping and assaulting a young woman he met on the Internet. After the verdict was read, the Columbia University graduate student wept quietly in the Manhattan courtroom.

After a three-week trial, the jury found that Jovanovic had imprisoned the young woman and assaulted her over two days in November 1996. Jurors rejected the defense's claim that the encounter between Jovanovic and the young woman was consensual.

Jovanovic, 31, who is scheduled to be sentenced May 6, faces a minimum penalty of 15 years to life in prison and a maximum of 25 years to life.

The case drew public attention because Jovanovic, a doctoral student in microbiology at Columbia, met his accuser in an Internet chat room. The young woman, at the time a 20-year-old Barnard College student, testified that Jovanovic attracted her interest during an extended e-mail correspondence, and convinced her to accompany him on a date.

But the young woman, whose name is being withheld because of the nature of the crime, said that after bringing her to his Washington Heights apartment, Jovanovic tied her to a futon frame and tortured her for more than 20 hours.

The young woman, whose testimony lasted several days, said Jovanovic threatened to kill her, bit her until she bled, burned her with wax and beat her with a stick.

Prosecutors declined to make any comment after Wednesday's verdict.

Defense lawyers had claimed that the young woman made up a story about what was a consensual sexual encounter. But the prosecutor in the case, Gail Heatherly, countered that the young woman had given a consistent account of the attack, had suffered physically and emotionally, and had no motive to lie. In Ms. Heatherly's closing statement, she characterized Jovanovic as "deceptive, deceitful and dishonest."

"She doesn't know Oliver's last name," Ms. Heatherly told the jury. "She doesn't know where he lives. She met him one night, and now she has made it her life's goal to ruin his life?"

At a press conference after the verdict, Jovanovic's lawyers and his family expressed their dismay and said they would appeal.

"I am totally devastated," said Jovanovic's mother, Sabina. "Once I fall apart, I will not be able to collect myself. Oliver, we know is innocent."

Defense lawyers said that prosecutors had offered to strike a plea bargain before the verdict, but Jovanovic declined. Fred Sosinsky, one of his lawyers, declined to describe the terms of the proposed agreement, but said the proposed sentence was "shockingly, surprisingly low."

"The numbers that were proposed were reflective of their view of the case," Sosinsky said.

Jovanovic's lawyers argued Wednesday that the trial judge, state Supreme Court Justice William Wetzel incorrectly restricted the evidence that defense lawyers could present. They said that Wetzel's decisions had prevented them from making a case that would have established Jovanovic's innocence.

"A travesty of justice has occurred," Jack Litman, Jovanovic's lead lawyer, said at the news conference following the trial. "An innocent man faces life imprisonment because this American jury has heard only half the evidence."

At the heart of the defense's complaint is the judge's interpretation of New York's rape-shield law. The law, which is intended to protect rape victims, prevents the defense from presenting evidence of the accuser's past sexual history except under narrowly defined circumstances.

A bitter argument raged throughout the trial regarding evidence that the judge excluded under the law. Because Wetzel sealed the records of the argument, that argument was carried out in secret. But defense lawyers Wednesday described some of the issues they intended to use to appeal the verdict.

Without being specific, the defense lawyers said that in an e-mail correspondence with Jovanovic, the young woman wrote messages that would have led the jury to give credence to the defense argument that what occurred was not an assault.

Wetzel did not allow the messages to be used as evidence, the defense lawyers said, finding that they were excluded by the shield law.

The defense lawyers said that the judge's ruling also prevented the jury from hearing important evidence about Jovanovic's state of mind before the incident, as well as the young woman's. They said the information could have been used to impeach the young woman's credibility on the witness stand.

The lawyers said that courts in other states have held that speech between a criminal defendant and an accuser is not sexual conduct, and therefore should be allowed as evidence. They said that the judge should have allowed the e-mail as evidence under that reasoning.

Sosinsky said the importance of the e-mail was not in what it shows about the previous behavior of the young woman, but in establishing what the two people intended when they met for the date.

"Whether it is true or not is irrelevant," he said. "It is certainly relevant to the defendant's state of mind."